Conventionally, there is a problem that the writing lead exposed from the tip end of the ferrule is easily broken when high writing pressure is applied to the writing lead when writing is performed using the mechanical pencil. If the writing pressure is constant, the writing lead is more easily broken as an angle between an axial direction of a body cylinder of the mechanical pencil and a paper surface becomes smaller (as the body cylinder is laid down) or as a length of the writing lead exposed from the tip end of the ferrule becomes longer.
With respect to such a problem, Patent Literature 1 (JP 2015-123689 A) discloses a mechanical pencil that reduces breakage of a writing lead when high writing pressure is applied to the writing lead by absorbing a component in an axial direction of the writing pressure and a component vertical to the axial direction of the writing pressure using different mechanisms, respectively.
Specifically, a ferrule is supported by a body cylinder via an elastic body (coil spring), and the ferrule has a cam slope that gradually decreases in diameter toward a rear side in the axial direction in the mechanical pencil disclosed in Patent Literature 1. In addition, a pressing portion that presses the cam slope in a front side in the axial direction is formed in the body cylinder. With such a configuration, the cam slope of the ferrule is pressed to the front side in the axial direction by the pressing portion of the body cylinder due to the component vertical to the axial direction of the writing pressure (a force in a radially outward direction of the body cylinder), and the ferrule slides forward (pops out) from a tip end of the body cylinder. Accordingly, the length of the writing lead exposed from the tip end of the ferrule is decreased.
Further, a lead releasing unit that releases the writing lead is supported by the body cylinder to be relatively movable in the axial direction in the state of being biased to the front side in the axial direction (in a ferrule tip end direction in the axial direction) by the elastic body (coil spring) in the mechanical pencil of Patent Literature 1. Then, the component in the axial direction of the writing pressure is absorbed as the lead releasing unit including the writing lead relatively moves to the rear side in the axial direction with respect to the body cylinder. As a result, the length of the writing lead exposed from the tip end of the ferrule is further reduced so that the breakage of the writing lead is decreased.